Abstract Gallosilicate zeolite (Ga-Silicate-1) was synthesized and characterized by wet chemical analysis, Fourier transform infrared spectroscopy, X-ray diffraction, BET surface area analysis and 29Si MAS NMR. The prepared Ga-Silicate-1, calcined in the temperature range from 350°C to 550°C, was tested as a catalyst for the synthesis of propylene carbonate (PC) from CO2 and propylene oxide in a solvent-free reaction. The effects of various parameters, such as co-catalyst, reaction temperature, reaction time, and pressure of CO2, on the reaction were investigated. It has been found that increasing the calcination temperature from 500°C to 550°C decreased both the conversion and selectivity to PC from 63.7% to 20.6% and from 77.6% to 58.9%, respectively. Unlike conversion and selectivity, the surface area increased from 96.1 to 103.8 m2/g. This significant increase in surface area due to the degalliation of the zeolite, along with the decrease in conversion, clearly indicates the role of gallium in the production of PC. Under mild reaction conditions (75°C and P (CO2) = 0.55 MPa), a conversion of 70.8% and a selectivity of 81.3% were obtained. Based on the obtained results, a mechanism for the synthesis of PC over the Ga-Silicate-1 catalyst was proposed.

中文翻译：

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Ga-Silicate-1催化剂上环氧丙烷和CO2合成碳酸丙烯酯

摘要 合成了镓硅酸盐沸石（Ga-Silicate-1），并通过湿化学分析、傅里叶变换红外光谱、X射线衍射、BET表面积分析和29Si MAS NMR对其进行了表征。制备的 Ga-Silicate-1 在 350°C 至 550°C 的温度范围内煅烧，被测试作为无溶剂反应中由 CO2 和环氧丙烷合成碳酸亚丙酯 (PC) 的催化剂。考察了助催化剂、反应温度、反应时间、CO2压力等各种参数对反应的影响。已经发现，将煅烧温度从 500°C 提高到 550°C，PC 的转化率和选择性分别从 63.7% 降低到 20.6% 和从 77.6% 降低到 58.9%。与转化率和选择性不同，表面积从 96.1 增加到 103.8 m2/g。由于沸石的脱镓，表面积的显着增加，以及转化率的降低，清楚地表明了镓在 PC 生产中的作用。在温和的反应条件下（75°C 和 P (CO2) = 0.55 MPa），获得了 70.8% 的转化率和 81.3% 的选择性。基于所得结果，提出了在Ga-Silicate-1催化剂上合成PC的机理。